The present disclosures relate to semiconductor devices, and more particularly, to a method of making a multiple crystal orientation semiconductor device.
Substrates with Dual Orientation (DSO) are desirable because they allow taking advantage of enhanced electron and hole mobility in the (100) and (110) crystal orientations, respectively. In one method of making a dual orientation substrate, the method requires etching through the buried oxide (BOX) to access the bottom substrate. The bottom substrate provides the alternate Si plane to the SOI layer. However, dry etching through the BOX and stopping on bottom Si substrate can induce damage on the Si surface of the bottom substrate. This damage can negatively impact the selective Si epitaxy process, thus resulting in dislocations in the active area of the selective Si epi. Thus, the damage is detrimental to subsequently formed devices since the damage induces defects into the channel epi.
Accordingly, there is a need for an improved method for overcoming the problems in the art as discussed above.
The use of the same reference symbols in different drawings indicates similar or identical items. Skilled artisans will also appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve the understanding of the embodiments of the present invention.